diff --git a/depends/pack200/anti200.cpp b/depends/pack200/anti200.cpp
index 3dfdb5dc..1e1ec0c8 100644
--- a/depends/pack200/anti200.cpp
+++ b/depends/pack200/anti200.cpp
@@ -8,21 +8,36 @@
 
 int main(int argc, char **argv)
 {
-	if (argc == 3)
+	if (argc != 3)
 	{
-		try
-		{
-			unpack_200(argv[1], argv[2]);
-		}
-		catch (std::runtime_error &e)
-		{
-			std::cerr << "Bad things happened: " << e.what() << std::endl;
-			return EXIT_FAILURE;
-		}
-		return EXIT_SUCCESS;
-	}
-	else
 		std::cerr << "Simple pack200 unpacker!" << std::endl << "Run like this:" << std::endl
 				  << "  " << argv[0] << " input.jar.lzma output.jar" << std::endl;
-	return EXIT_FAILURE;
+		return EXIT_FAILURE;
+	}
+
+	FILE *input = fopen(argv[1], "rb");
+	FILE *output = fopen(argv[2], "wb");
+	if (!input)
+	{
+		std::cerr << "Can't open input file";
+		return EXIT_FAILURE;
+	}
+	if (!output)
+	{
+		fclose(output);
+		std::cerr << "Can't open output file";
+		return EXIT_FAILURE;
+	}
+	try
+	{
+		unpack_200(input, output);
+	}
+	catch (std::runtime_error &e)
+	{
+		std::cerr << "Bad things happened: " << e.what() << std::endl;
+		fclose(input);
+		fclose(output);
+		return EXIT_FAILURE;
+	}
+	return EXIT_SUCCESS;
 }
diff --git a/depends/pack200/include/unpack200.h b/depends/pack200/include/unpack200.h
index bcee8009..f9239488 100644
--- a/depends/pack200/include/unpack200.h
+++ b/depends/pack200/include/unpack200.h
@@ -34,4 +34,4 @@
  * @return void
  * @throw std::runtime_error for any error encountered
  */
-void unpack_200(std::string input_path, std::string output_path);
+void unpack_200(FILE * input, FILE * output);
diff --git a/depends/pack200/src/unpack200.cpp b/depends/pack200/src/unpack200.cpp
index 0a9d2714..22b7f3b0 100644
--- a/depends/pack200/src/unpack200.cpp
+++ b/depends/pack200/src/unpack200.cpp
@@ -94,20 +94,9 @@ static int read_magic(unpacker *u, char peek[], int peeklen)
 	return magic;
 }
 
-void unpack_200(std::string input_path, std::string output_path)
+void unpack_200(FILE *input, FILE *output)
 {
 	unpacker u;
-	FILE *input = fopen(input_path.c_str(), "rb");
-	if (!input)
-	{
-		throw std::runtime_error("Can't open input file" + input_path);
-	}
-	FILE *output = fopen(output_path.c_str(), "wb");
-	if (!output)
-	{
-		fclose(output);
-		throw std::runtime_error("Can't open output file" + output_path);
-	}
 	u.init(read_input_via_stdio);
 
 	// initialize jar output
diff --git a/logic/net/ForgeXzDownload.cpp b/logic/net/ForgeXzDownload.cpp
index 83cbabd0..359ad858 100644
--- a/logic/net/ForgeXzDownload.cpp
+++ b/logic/net/ForgeXzDownload.cpp
@@ -311,18 +311,51 @@ void ForgeXzDownload::decompressAndInstall()
 	m_pack200_xz_file.remove();
 
 	// revert pack200
-	pack200_file.close();
-	QString pack_name = pack200_file.fileName();
-	QString source_native = QDir::toNativeSeparators(pack_name);
-	QString target_native = QDir::toNativeSeparators(m_target_path);
+	pack200_file.seek(0);
+	int handle_in = pack200_file.handle();
+	// FIXME: dispose of file handles, pointers and the like. Ideally wrap in objects.
+	if(handle_in == -1)
+	{
+		QLOG_ERROR() << "Error reopening " << pack200_file.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	FILE * file_in = fdopen(handle_in,"r");
+	if(!file_in)
+	{
+		QLOG_ERROR() << "Error reopening " << pack200_file.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	QFile qfile_out(m_target_path);
+	if(!qfile_out.open(QIODevice::WriteOnly))
+	{
+		QLOG_ERROR() << "Error opening " << qfile_out.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	int handle_out = qfile_out.handle();
+	if(handle_out == -1)
+	{
+		QLOG_ERROR() << "Error opening " << qfile_out.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	FILE * file_out = fdopen(handle_out,"w");
+	if(!file_out)
+	{
+		QLOG_ERROR() << "Error opening " << qfile_out.fileName();
+		failAndTryNextMirror();
+		return;
+	}
 	try
 	{
-		unpack_200(source_native.toStdString(), target_native.toStdString());
+		unpack_200(file_in, file_out);
 	}
 	catch (std::runtime_error &err)
 	{
 		m_status = Job_Failed;
-		QLOG_ERROR() << "Error unpacking " << pack_name.toUtf8() << " : " << err.what();
+		QLOG_ERROR() << "Error unpacking " << pack200_file.fileName() << " : " << err.what();
 		QFile f(m_target_path);
 		if (f.exists())
 			f.remove();
diff --git a/mmc_updater/src/Platform.h b/mmc_updater/src/Platform.h
index 6d9afdfb..97867d6a 100644
--- a/mmc_updater/src/Platform.h
+++ b/mmc_updater/src/Platform.h
@@ -13,7 +13,9 @@
 
  // disable warnings about exception specifications,
  // which are not implemented in Visual C++
- #pragma warning(disable:4290)
+    #ifdef MSVC
+        #pragma warning(disable:4290)
+    #endif
 #endif
 
 #ifdef __APPLE__